The present invention relates to a twin belt conveyor apparatus which comprises a pair of flat belts each of which rotates endlessly in opposite directions, materials being put and conveyed between the belts which run in the same direction.
In a belt conveyor having a large lift and a high transportation rate for transferring excavated earth, iron ore or aggregates, a main conveyor belt and an auxiliary belt are provided. Materials are thrown onto the main belt, and covered with the auxiliary belt. The materials are conveyed by driving both the belts.
FIG. 7 denotes a view which shows all of a conveyor apparatus, in which 31 denotes a main flat belt which is wound between a head pulley 32 and a tail pulley 33. The head pulley 32 is connected to drive means, and materials are put from a hopper 34 onto the lower end of the main belt 31 for conveying. An auxiliary belt 35 comprises a flat belt with which the materials on the main belt 31 are covered, and is wound between a head pulley 36 and a tail pulley 37. The auxiliary belt 35 is rotated along the main belt 31 by drive means connected to the head pulley 36.
FIG. 8 is a top plan view of the head pulleys 32 and 36 of the main and auxiliary belts 31 and 35. To one end of the head pulley 32, an output shaft of a reduction gear 42 connected to a motor 43 is connected via a shaft coupling 41. The head pulley 36 of the auxiliary belt 35 is connected via a shaft coupling 44 to a reduction gear 45 connected to a motor 46.
In an apparatus in which the main and auxiliary belts 31 and 35 are driven by each of the motors 43 and 46, the head pulleys 32 and 36 which comprise drive pulleys become different in rotation speed, depending on the features of the motors 43 and 46, difference on load between the main and auxiliary belts 31 and 35, difference in feed of the motors involved by the load and errors in reduction gear ratio of the reduction gears 42 and 45. The difference in rotation speed between the main and auxiliary belts 31 and 35 becomes difference in running speed between them. Thus, during operation of the conveyors, the belts are always rubbed together, thereby increasing wear and generating noise.
In a steep slope conveyor apparatus, the drive pulleys for the main and auxiliary belts 31 and 35 are very different in installation height, and thus, it is necessary to provide drive means and supporting means therefor separately. It increases costs of two drive means and high noise makes environment worse.